html,body{
    background-color: aqua;
    .box{
        width: 220px;
        height: 120px;

        background: url('../images/tupian.jpg');
        background-size: cover;
    }
    .box2{
        width: 220px;
        height: 120px;

        background: url('../images2/tupian.jpg');
        background-size: cover;
    }
}